Abstract 1229: Neoadjuvant therapy alters collagen architecture of pancreatic cancer

Treatment of pancreatic cancer remains clinically challenging and requires the novel therapeutic interventions to improve patient outcome. Neoadjuvant therapy i.e. preoperative treatments comprising chemotherapeutic agents with/without radiation offers down-staging and improvement of surgical resectability. Here, we report that neoadjuvant therapy alters collagen architecture of pancreatic cancer. Transcriptomic profiles of type 1 to type 28 collagens depicted changes of collagen composition due to neoadjuvant therapy. Immunohistochemically, the expressed area of collagen type 1, 3, 4, and 5 were significantly reduced post treatment. The bioinformatic approaches provided a comprehensive insight into treatment-induced matrix remodeling, which showed that Ephrin-A signaling and Ephrin-A5 appeared as a highly possible pathway and a crucial ligand. Ephrin-A5 co-localized with alpha-SMA(+) cancer-associated fibroblasts, whereby Ephrin-A5 have been implicated to synthesize collagens. The Ephrin-A5 positive cells significantly reduced after neoadjuvant therapy, also inversely correlated with tumor shrinkage rate. Using primary culture cells of cancer-associated fibroblasts, experimental exposure of radiation and chemotherapeutic agents suppressed the proliferation of cancer-associated fibroblasts, collagen synthesis and Ephrin-A5 expression. Thus, our studies demonstrate that neoadjuvant therapy down-regulates Ephrin-A5 expression, leading to a change of extracellular matrix structure. It should be a clinical concern of surgical handling when following resection.

Note: This abstract was not presented at the meeting.

Citation Format: Kosei Nakajima, Yoshinori Ino, Sotoshi Nara, Toshimitsu Iwasaki, Nobuyoshi Hiraoka. Neoadjuvant therapy alters collagen architecture of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1229.

Coexistence of Ferromagnetic and Stripe-Type Antiferromagnetic Spin Fluctuations in YFe_{2}Ge_{2}

We report neutron scattering measurements of single-crystalline YFe_{2}Ge_{2} in the normal state, which has the same crystal structure as the 122 family of iron pnictide superconductors. YFe_{2}Ge_{2} does not exhibit long-range magnetic order but exhibits strong spin fluctuations. Like the iron pnictides, YFe_{2}Ge_{2} displays anisotropic stripe-type antiferromagnetic spin fluctuations at (π, 0, π). More interesting, however, is the observation of strong spin fluctuations at the in-plane ferromagnetic wave vector (0, 0, π). These ferromagnetic spin fluctuations are isotropic in the (H, K) plane, whose intensity exceeds that of stripe spin fluctuations. Both the ferromagnetic and stripe spin fluctuations remain gapless down to the lowest measured energies. Our results naturally explain the absence of magnetic order in YFe_{2}Ge_{2} and also imply that the ferromagnetic correlations may be a key ingredient for iron-based materials.

Immune landscape of neoadjuvant/preoperative chemoradiotherapy in pancreatic cancer

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Background: Neoadjuvant/preoperative chemoradiotherapy in pancreatic cancer has been implicated to induce a local anti-tumor immunity, however the molecular mechanism remains a conundrum. Methods: Two patients’ cohort samples with/without preoperative chemoradiotherapy were used (n = 26 and n = 20, respectively). The treatment-driven immune microenvironment changes were analyzed by stratified bioinformatic approaches i.e. heat map analysis of immune-related genes selected by Gene Ontology, GSEA with Immunologic Signature data base, and Ingenuity Pathway Analysis (IPA). The results were further validated by immunohistochemical approaches. Results: Preoperative treatment induced 212 genes including DC-SIGN (CD209) and 13 immune-associated pathways such as TCR signaling, with an increasing shift of CD8 T-cell population by upregulation of MAL (T-cell differentiation protein). Consistently, immunohistochemical findings showed that the accumulation of DC-SIGN (+) dendritic cells and MAL (+) lymphocytes were significantly increased in patients with preoperative therapy. Conclusions: Preoperative chemoradiotherapy induces a shift toward CD8 T-cell generation mediated by DC-SIGN (+) dendritic cells and MAL (+) lymphocytes, leading to enhance anti-tumor immunity.

Reduction of intrapancreatic neural density in cancer tissue predicts poorer outcome in pancreatic ductal carcinoma

Neural invasion is one of the malignant features contributing to locally advanced and/or metastatic disease progression in patients with pancreatic ductal adenocarcinoma (PDAC). Few studies exist on the distribution and state of nerve fibers in PDAC tissue and their clinicopathological impacts. The aim of the present study was to investigate the clinicopathological characteristics and prognostic value of intrapancreatic neural alterations in patients with PDAC. We retrospectively analyzed 256 patients with PDAC who underwent macroscopic curative surgery. Nerve fibers, immunolabeled with a specific neural marker GAP-43, were digitally counted and compared among PDAC, chronic pancreatitis (CP) and normal pancreatic tissues. Interlobular nerve fibers were apparently hypertrophic in both CP and PDAC, although intrapancreatic neural density and nerve number decreased characteristically in PDAC. They tended to decrease toward the center of the tumor. Kaplan-Meier survival analyses revealed a statistically significant correlation between low neural density and shorter overall survival (OS) (P = 0.014), and between high neural invasion and shorter OS (P = 0.017). Neural density (P = 0.04; HR = 1.496; 95% CI 1.018-2.199) and neural invasion ratio (P = 0.064; HR = 1.439; 95% CI .980-2.114) were prognostic factors of shorter OS in the multivariate analysis. These findings suggest low intrapancreatic neural density in patients with PDAC as an independent prognosticator, which may represent aggressive tumor behavior. Furthermore, we propose a simple, practical and reproducible method (to measure neural density and the neural invasion ratio during conventional histopathological diagnosis of PDAC), which has been validated using another cohort (n = 81).

Abstract P2-14-09: A novel nipple aleolar complex involvement predictive index (NACPI) for indicating nipple sparing mastectomy in breast cancer patients

Background: While Preservation of NAC is concerned to increase the risk of local recurrences in the retroareolar glandular tissue, nipple sparing mastectomy (NSM) is increasing in patients with breast cancer and has been shown to result in better cosmetic outcome and the benefit for quality-of-life. It is necessary to predict accurately NAC involvement in order to select which patients may be candidates to NSM. The distance from the nipple to the tumor (DNT) is proposed as one of the best criteria to select the patient. The purpose of this study is to identify the predictors of NAC involvement retrospectively and to develop a clinical predictive model to select the patients who can be offered preservation of NAC.Methods: A total of 168 patients with primary operable breast cancer who received subcutaneous mastectomy for breast reconstruction at Saitama Medical Center during July 2013 to December 2017 were selected from the hospital's surgical database. NAC involvement was defined by the presence of invasive carcinoma and/or ductal carcinoma in situ at the subareolar margin.

Results: Of the 148 patients who were preserved NAC, 89.9% (133/148) were NAC involvement negative and 10.1% (15/148) were positive in permanent pathological specimens. Of the 20 patients who were resected NAC, NAC involvement positivity was only 50.0% (10/20). This revealed that NAC involvement with a sensitivity (SN) of 40.0%, a specificity (SP) of 93.0%, a positive predictive value (PPV) of 50.0% and a negative predictive value (NPV) of 89.9% (AUC=0.665, 95%CI: 0.5345-0.796). In 140 patients who were performed intraoperative sub-nipple frozen section biopsy, the findings was significantly associated with NAC involvement (P<0.001), and which predict the NAC involvement with a SN of 93.3%, a SP of 89.6%, a PPV of 51.9%, and a NPV of 99.1% (AUC=0.915, 95%CI: 0.835-0.994). In the concordance rate between frozen section findings and definitive pathologic results, DCIS was 53% (9/17), atypical cell was 50% (2/4) and invasive ductal carcinoma was 100% (3/3). Correlation between NAC involvement and clinicopathological factors, tumor size ≥4cm (P<0.001), DNT <1cm by MMG (P=0.002), DNT <1cm by MRI (P<0.001), nipple contrast findings by MRI (P<0.001), tumor in central portion (P<0.001), multicentirc/focal lesion (P<0.001), c(N) positive (P=0.014) were significant relation with NAC involvement. Each predictors were scored 0 or 1, and the total score of 0-3 points was defined as low risk, 4 points as intermediate risk, and 5-7 points as high risk. Depending on this categorized classification, the NAC involvement rate was 3.5% (5/142) in low risk, 68.7% (11/16) in intermediate risk, 90.0% (9/10) in high risk and there was a significant correlation between the risk group and NAC involvement (P <0.001). Notably, assuming that NAC is preserved for low risk patients and is resected for intermediate and high risk patients, NACPI contributes to improve the accuracy of selecting the surgical procedures (SN 80.0%, SP 95.8%, PPV 76.9%, NPV 96.5% (AUC=0.879, 95%CI: 0.784-0.974)).Conclusion: This study suggests that NACPI can help us indicating subcutaneous mastectomy for the breast cancer patients who request preserve NAC with more oncological safety.

Citation Format: Seki H, Sakurai T, Shimizu K, Mizuno S, Tokuda T, Kaburagi T, Seki M, Karahashi T, Nakajima K. A novel nipple aleolar complex involvement predictive index (NACPI) for indicating nipple sparing mastectomy in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-14-09.